inaccessible_boot_device - after Multiprocessor Upgrade

I have a problem with a recent Dell server upgrade I recently did. I have a 1600sc with two Xeon processors in it. Apparently I didn't let Windows 2000 Server know there were two processors when I did the upgrade so it only installed the single processor driver for the machine. I went into Computer Management and opened the COMPUTER item listed in Device Manger. Under that icon I noticed it said Single Processor PC so I upgraded that driver to ACPI Multiprocessor PC (included driver from Microsoft). This is the same driver my other 1600sc is using with two processors.

The machine then asked me to reboot, and I said YES. It begins to boot up and gets past the bios (the bios posts reads two processors as well). Once it gets to the Loading Windows 2000 Server screen it quits about two thirds of the way and give a stop error of "inaccessible boot device". I have gone into the recovery console and tried the FIXBOOT utility as well as replacing the SYSTEM hive (winnt\system32\config\system) with the default hive (winnt\repair\system), but had no success upon reboot.

I am not familiar with all the tool available to me in the recovery console, but I was hoping that I could adjust the processor driver back to the original somewhere in the recovery console. The only other variable that I must mention is that I have a RAID 5 (PERC4/SC card from Dell) configuration on the boot drive. It is a 36 gig raid divided into a 10gig (C Drive) and 27 gig (D Drive). The boot partition is the C drive of this RAID. I am able to access both partitions once I load the special PERC drivers and enter the recovery console as Administrator.

If for some reason I can not recover this machine I was considering doing a Parallel Install on the C drive and then trying to RESTORE the registry so that I would keep all the files in place on the C & D drive and once the registry hive was replaced I it would operate as it used to without needing to install all the programs again.http://support.microsoft.com/default.aspx?scid=kb;EN-US;266465

Any comments or feedback or help on getting this machine fixed would be greatly appreciated.

I believe it's generally accepted that you cannot change the number of processors running on a W2K server OS. You need to re-install windows. I personally don't know if a repair installation will do the trick, but I doubt it.

HAL (or Hardware Abstraction Layer) is changed via the computer type at the top of device manager.

This is the interface between your hardware and the OS that everything interacts with.

You cannot change this type because the PnP device tree in the registry is totally different between the two and when you try to boot one OS type with a hardware tree of another type created only during initial OS installing, it cannot find ANY hardware including the drive controller and thus the misleading error inaccessible_Boot_Device.

Read this entire article BEFORE changing the HAL at all. With this info you can enable SMP safely and revert back quickly if you screw up.

Be sure you have the appropriate bootable OS CD that is the proper service pack. If you have one but not the right service look up SLIP STREAMING to apply your SP to an OS installation image. Also ALREADY have a floppy with your boot controller driver ready so you can initiate WIndows 2000 Setup with drive access. Remember to verify your server has a floppy drive that Setup recognizes as A drive and get a compatible USB floppy drive if you need to.

Be sure to hit F6 and F7 so you can load your hard drive driver AND pick the CORRECT HAL.

When you run the emergency repair process to fix your HAL screwup, it will ask what to do with each file it finds that is different from the CD. Hit ESC for EVERY FILE EXCEPT: